SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19ca621ed8281bde67a8818ee83a72e7d321bf2be6dc3b7e6414a7144b7118fd' 
  AND token = 'hJzZQQLf3PpSGc+P3Mbk33UXB8sQUkG3CxS/Kz2cBDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}